Coupling environment with PHP session info, avoids injector troubles

I'd rather have Session::get('TestSessionId') being passed in
as an identifier, but the env object is passed around so much
as a singleton that its easy to forget that argument,
and cause hard to debug errors. We need a global "app" object
which all other objects can reference somehow.

code/TestSessionController.php

@@ -30,7 +30,7 @@ class TestSessionController extends Controller {
 	public function __construct() {
 		parent::__construct();
 
-		$this->environment = Injector::inst()->get('TestSessionEnvironment', Session::get('TestSessionId'));
+		$this->environment = Injector::inst()->get('TestSessionEnvironment');
 	}
 
 	public function init() {

code/TestSessionEnvironment.php

@@ -54,7 +54,12 @@ class TestSessionEnvironment extends Object {
 	public function __construct($id = null) {
 		parent::__construct();
 
-		$this->id = $id;
+		if($id) {
+			$this->id = $id;
+		} else {
+			Session::start();
+			$this->id = Session::get('TestSessionId');
+		}
 	}
 
 	/**
@@ -75,6 +80,20 @@ class TestSessionEnvironment extends Object {
 		return(file_exists($this->getFilePath()));
 	}
 
+	/**
+	 * @param String $id
+	 */
+	public function setId($id) {
+		$this->id = $id;
+	}
+
+	/**
+	 * @return String
+	 */
+	public function getId() {
+		return $this->id;
+	}
+
 	/**
 	 * Creates a temp database, sets up any extra requirements, and writes the state file. The database will be
 	 * connected to as part of {@link self::applyState()}, so if you're continuing script execution after calling this

code/TestSessionRequestFilter.php

@@ -10,10 +10,7 @@ class TestSessionRequestFilter {
 	protected $testSessionEnvironment;
 
 	public function __construct() {
-		$this->testSessionEnvironment = Injector::inst()->get(
-			'TestSessionEnvironment',
-			Session::get('TestSessionId')
-		);
+		$this->testSessionEnvironment = Injector::inst()->get('TestSessionEnvironment');
 	}
 	
 	public function preRequest($req, $session, $model) {